Air-compressor.



P. H. REAHDON.

Patented May 30, 1916.

2 SHEETS-SHEET l- W I INVENTOR, WITNESSES: I EH IPS/IRDO/V Afi GyUZLlZI/ld/L KM ATTORNEYS.

P. H. REARDON.

AIR COMPRESSOR.

APPLICATION FILED JULY 22,1914.

1 ,1 @%99@, Patented May 30, 1916.

2 SHEETS-SHEET 2.

WITNESSES IN VENTOR.

PM REHRUON.

M, ATTORNEYS.

rarnick H."REARDOI\I, or SAN Franc sco, oALIronnr'a.

am-ooiarniisson.

To allwhomc't may concern:

Be it known that I, PATRICK H. REARDON, a citizen of the United States, anda resident of the city and county of San Francisco,

State of California, have invented certain new and useful Improvements in Air-Compressors, of which the following is a specifica'tion.

My invention relates t0- air compressors.

and has for its main object to extend their usefulness.

The ordinary type of compressor now 1n general use employs puppet valves controlled by springs. This results in certain undesirable effects. In the great majority of installations these'eflects are not seriously detrimental. They do, however, limit the employment of this type of device and exclude it from a. large field of usefulness, for which it is otherwise adapted. I

So an object of the present inventlon, stated generally, is'to provide a compressor, which, while maintaining an equally high or producing a greater efliciency' than puppet valve compressors, avoids the undesirable effects referred to.

An ordinary puppet valve, owing to its inherent characteristics, is sudden in its opening and non-positive in its action. The necessarypresence of its spring makesit especially so ,in closing, that is to say, it hammers and flutters.- Many attempts have been made to remedy its defects by various means, such as reducing the area of its seat, adjustment of the springs, and

lightening its weight. These, however, arev ineffective, and particularly so when it is attempted to enlarge the effectiveness of a given compressor by increasing its speed.

This whole matter of compressor valves is beset by mechanical difficulties which confine to narrow limits the'possibility of variations in puppet valves looking'to ward the elimination-of their objectionable effects.

Hammering of the puppet valve upon its seat has heretofore necessitated a large margin of safety, and consequent wei ht of valve to insure a reasonable length 0 service, and avoid, to the greatest possible extent, that ever present source of disaster in compressors, the fracture of a valve, and the introduction of a'frag m'ent into the compressor cylinder. l

Reduction in seat area'shortens the life of avalve and reducing the strength of a Specification of Letters Patent.

controlling spring enhances the undesirable Patented May 3Q, I916. Application filed July 22, 1914. Serial No. 852,379.

Thus it'comes about in.

order to open the valve against the lesser 1 pressure on the opposite side/ This results in a violent or popping action of the valve the lnstant contact of the valve with its seat is broken and the larger area of the valve surface exposed to the higher pressure beneath the valve which is avoided in the type of valve herein employed to a large extent by the inherent superficial flexibility of the valve. Thenthe peculiar characteristic of coil springs, that their resistance increases with their compression, adds another difficulty, which, with the previously describedv defect increases the hammering by a rebound from the spring. The result of all these factors is that the stream of air under pressure is in the form of pulsations brought about by the conflict between the popping open, the momentum and the inertia of the valve, and the necessarily varying resistance of its opposing spring. Owing largely to these conditions, the indicator card taken from the compressor difiers characteristically from that taken from the steam engine, in that its lines are wavy through awide range. However, aside from these 'undesirable effects'which, as has already been intimated, do not materially affect the usefulness of compressors in a large majority of employments, the ordinary puppet valve, owing to its simplicity, reliability, ease of repair and of renewal, and itsinstantaneous action, is exceptionally adaptedgto compressor use and hence it has firmlyif'establislied itself in the compressor art for the control 'of air to and from the compressor cylinder:

' Both of these characteristics of the ordinary compressor, its noise and the pulsatory' character of the outflowing current, exclude it largely from hotels, hospitals, mechanical surgery, dentistry work, and the like. In the first two possible utilities, it is unavailable owing to the noise which is conveyed through the building by the pipes. In the others, owing to theefi'ect of the pulsations 'on the speed of the tools employed andv op the nerves of the patients. Another bbject of my invention, therefore, is the solution of the problem to provide a compressor of simple construction which will produce an indicator card practically free from the wavy lines characteristic of the ordinary compressor card by diminishing-the pulsations in the outgoing stream of air which produce'them. And another object is to provide with the foregoing char- I 'acteristi'cs a compressor'noiseless in its operation. And a further object is to provide a compressor with theforegoing capabilities which, in addition thereto, is inherently capable of being run at a speed greater than is practicable with ordinary puppet valves.

For efliciency it is desirable that the passage for the outgoing compressed air and the passage for theincoming air shall be freely open-to these oppositely traveling currents to, avoid"wi're drawing the air. And

I further, that thefree opening from the cylinderto the pipe line shall not be closed till all ofthe compressed air is forced outof the cylinder by the piston stroke; Employ- "ment .of eccentrics to perform intermittent cam functions necessarily involved irf'timing the'combined inlet and outflow of air under compressor conditions is precluded by difficulties-and objections heretofore met theinherent character'of themotion producedby' the eccentric, it being uniform,

non-intermittent and sluggish, and otherwise unadapted to meet the requirements of the rapid and speed varying motions required at the end of the piston stroke to' properly direct the currents of air to and from the cylinder under compressor condi-' tions This disadvantage of'the eccentric is 'PI'OVldBd for in the present constructionby limiting its action to the intakevalv'e, at Y which point it may be advantageouslyem ployed.

I The invention herein jconsists'broa-dly' in.

the employment of a valve for the intakeof the air and a super-,

mechanically operated ficially flexible and inherently resilient-metallic pressure controlled valve for theoutlet of the air. These diverse forms of valves and their applicatioin meet and provide for the inherent peculiarities of the action. of

- air under the conditions at the inflow and outflow :in compressors and' overcome the w1th in compressor. practice. The actionof the air at the intake and outflow is whhlly different, and each brings about itsvown pepuliar difficulties- As the piston starts to move to take in air, 'a' reduction ofrpre'ss ure is produced in the cylinder which with the pu pet valve at the inlet is responded to su denly till anyapproximat e equalization between the inside pressure and the outside atmospheric pressure is reached. In 'a slow speedcompressorl'this alternate opening and closing of the puppet'valve results in a succession of valve openings and seatings,hav'

ing a relation tothe. tension of the spring a controlling the puppetvalve. As. the speed of the compressor 15' increased these openings and closings develop into an impractical u fluttering of'the valve with its consequent .rapid deterioration by hammering. Apart from this undesirablea action, a point. is

early reached at whichiaii-further' increase of speed brings about no additional increase of the amount of air compressed. Furthermore, a pointis soon' fre'ached in which a partial vacuum is maintained in the cylinder during the whole of the intake stroke, the

amount of vacuum increasing with the speed of the compressor. Thusconceivably thespeed of the pistonLcould be so great that the puppet valvefspring would throw the puppet valve back to its seat before more than a negligible amount of air had passed through the. valve opening, and under most favorable conditions of- 'normally high speed the nature of" the puppetfvalve brin 5 about a destructive hammering of the va ve and the fluttering rattle which precludes the employment of the compressorfrom some forms of service owing to its noisy character. Thus the mechanically operative mencement of the function is, of course, de-

pendent upon the pressure 1n the receiver,

. of receiver pressure... The point of com and usually occurs at a comparatively short distance from the end of the stroke- New, while during this. comparatively short distance of functional activity a puppet valve will act as in the inflow, its deleterious ef-* fects' cannot be so pronounced, as in intake conditions. With the ordinary puppet valve" they are still sufliciently deleterious to render the use of the ordinary. puppet valve undesirable. The necessary-weight of the ordinary puppet valve to provide for 'suf ficient strength for practicalservice is one of the principalelements' which brings aboutthe undesired and harmful hammering and noise incident to its sudden puppet action.

- While with the employment of a thin flexible plate valve with its extreme lightness of vweight and superficial flexibility, not only is i the destructive hammer and consequent noise greases avoided but also the puppet explosive opening is in a large measure also avoided. Thus by the combined action of these two types of valves, the mechanically operated one at the intake and the pressure actuated super-- ficially flexible valve at the outlet, the compressor is rendered noiseless and capable of aspeed of operation unavailable with the former type of puppet valve or with any other combination of valves of any kind of v the same cost of construction and upkeep, and with the consequent economy due to the absence of wear and tear not possible with the ordinary puppet valve compressor.

The invention possesses other advantageous features, some of which, with the fore going, will be set forth at length in the fol-' shown only one specific form of my generic invention, but it is to be understood that I do not limit myself to such form because my invention may be embodied in a multiplicity of forms, each being a speciesof my said invention. It is also to be understood that by the claim succeeding the description of my invention, I desire to cover the invention in whatever form it maybe embodied.

Referring to the accompanying drawings:

Figure 1 is an elevation of the compressor of my. invention, showing the inlet valve actuating means. Fig. 2'is a horizontal section through the cylinder head, showing the valve arrangement. Fig. 3 is a vertical section of the cylinder head taken on the line AA Fig. 2.

The compressor comprises a base 2 in which is journa'led the crank shaft 3, which is driven by power appliled to the wheel 4. Secured to the base 2 is the cylinder'5, containing the usual piston which is driven from the crank shaft 3 by suitable connect from the crank shaft 3 by a suitable connecting rod. -At the upper end of the cylinder is arranged the cyl nder head 6 in which.

are arranged the inlet and outlet valves.

Formed inthe cylinder head is the seat 7 in which the mechanically operated inlet valve 8 is disposed. The seat is provided with a port 9 which establishes communication between the air inlet 12 and the interior-of the seat and with a' port 13 which establishes communication between the cylinder 5 and the interior of the seat. The valve 8 is of the mechanically operated, oscillating type and is adapted to cut off and establish communication between the cylinder and the inlet. The valve 8 is light in weight and small in size relatively to the size of the cylinder and is oscillated by means of'the lever 14, which is connected to .the eccentric strap 15 surroundlng the eccentrio 16 on the crank-shaft 3 by theoonnectv ing rod 20 so that the valve moves in synchronism with the piston. Due to the lightness and small size of the valve and its small ar'c'ofmovement, it is possible to greatly increase the capacity of the compressor by operating it at high speeds, which high speed is obtained without pro ducing any vibration.

On account of the characteristics of com- PIGSSOI'S, that is, that air is drawn into the cylinder during substantially the whole of the suctionstroke and expelled during only a portion of the compression stroke, the eccentric, with its inherent sluggish motion, is adapted for the control of the inlet valve,

but is inefficient when applied to the outlet valve. The mechanically operated type of valve is more-efficient at the inlet than the puppet type of'..valve, because it permits a steady and continuous inflow 0 air during the suction stroke and is not subject to the deleterious fiutterings of the ordinary pup :pet valve.

The characteristics of compressors are such that it is advantageous to employ a pressure controlled valve at the outlet or discharge, but the inherent disadvantages of the ordinary .puppet valve are such that the use of the ordinary puppet valve preeludes the use of the compressor from'many forms of service and prevents the com.

trolled valve, 1 have employed a valve of pressor from being operated at a high speed. Toovercome these and other inherent-disadvantages of the ordinary pressure con- 'the puppet or pressure operated type which has all of the advantages of the ordinary puppet valve, where its advantages are highest, without any of its disadvantagw.

The outlet valve of the present invention comprises a thin metallic plate 17 su erficially flexible and inherently resilient. he plate 17 is preferably. formed in the shape of a disk and has an imperfora'te peripheral portion 18 which seats on the annular discharge port 19 formed'in the bottom wall 21 of the cylinder head. The discharge port is formed of a plurality of concentric-segmental passages, the ribs between the pas v sages senving to support the central core 22 to which the valve 17 is attached at its center. The valve is provided with one or 'more preferably concentric .slots or slits 23 -24 toprovide for the necessary superficial flexibility and the concentric slots or slits are preferably joined by slots or slits 25, whereby the flexibility is increased. The valve is formed of resilient metal, such as steel, and possesses inherent resiliency. so that the use of a spring to seat the valve is obviated, thereby producing a structure which not only possesses material advantages of operation over the ordinary puppet valve, but is cheaper in construction.

The present valve seats and unseats with .a rolling motion, another feature which distinguishes it from the ordinary puppet valve, and its consequent blow. The disk flexes upwardly in a curve, the periphery thereof preceding the portion which lies within the periphery. Means are also provided for limiting the unseating movement of the valve, so that it may not be subjected .to undue strains. Overlying the valve and in contact therewith at the center isa back- I ing plate 26 having a convex lower surface againstwhich the valve is moved when un backing plate air passes from the cylinder to the valve chamber 29 in the cylinder head, whence it discharges through the outlet port 31.

In the construction shown in Fig. 2 I have employed two discharge valves and the backing plate of one of the valves has been removed to disclose the construction of the valve.

By employing a mechanically operated valve at the inlet and a superficially flexible metallic valve at the outlet, I have provided a compressor which is not .only noiseless in operat1on,'but which is efiiciently operated at high speeds, thereby permitting a small compressor operated at high speed to have the same capacity as a large compressor of the ordinary type driven at standard speeds.

I claim:

A compressor comprising a stationary cylinder, a piston movable therein, a driven crank shaft to operate the piston, an air inlet of relatively small size with respect to the area of the cylinder, a mechanically operated rotary valve controlling the air inlet,

an outlet for the compressed air and a flexible metallic pressure operated" valve controlling the outlet.

In testimony whereof, I have hereunto set my hand at San Francisco, California, this 16th day of July 1914.

' PATRICK H. REARDON.

In presence of.

H. G. Pnos'r, M. LE CONTE. 

